Harbeth are more studio orientated than Spendor these days. If you look at their range, almost all of their higher end stuff has a studio equivalent.
One thing that I will say for Spendor is that if anything goes wrong, their after sales support is much better than Harbeth. I think Harbeth's orientation is actually more towards their export markets than the UK although clearly they have a BBC prescence. They are actually more commonly reviewed in the US/Canadian press than here.
The Harbeth speakers are a nice sound though. If you like BBC speakers, you'll like them.